The edge luminescence of CuGaSe2is studied on single crystals, from liquid helium temperature to room temperature. Time resolved spectroscopy measurements permit us to describe one of the emission bands in terms of donor‐acceptor pair transitions. Three other emission bands are observed. We attribute them to free‐to‐bound transitions. We determine three impurity levels: 110, 80, and 50 meV. Annealings in different atmospheres permit us to think that the 50‐meV level is due to a cation vacancy acting as an acceptor, and the 80‐meV level to a Se vacancy, which would act as a donor [Miglioratoetal., J. Appl. Phys. 46, 1777 (1975)].